Digital BW, The Print

----- Original Message -----
From: "Bruce Kinch" <pvx@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Friday, October 11, 2002 9:08 PM
Subject: Re: [Digital BW] Film for scanning was Re: The State of
PersonalScanner Technology


> >Martin wrote-
> >
> >None of the modern films has a shoulder to speak of and density is linear
to
> >exposure.
>
> I'm afraid this is incorrect.

Bruce,

I was talking about the higher density end of the curve, specifically the
shoulder. At what is normally considered maximum densities of 1.2 to 2.0 for
Zone X, I don't see any significant non-linear behavior with modern films
from Zone II to IX. Push them far enough and they will break down but I
think you will have lost any useable detail before you get that far. They
all have a toe of course and I was not suggesting they didn't. Overall, if a
film was significantly non-linear I suspect we wouldn't use it much.
Different films do have different characteristics but this is due to more
than just the different density vs. exposure relationship.

> Characteristic curves for virtually all
> films are available on the manufacturers' web sites, and comparisons
> are informative. (I know this because I just went through this with a
> class, where we plot curves and compare to the "official" version).
> Tri X Pan, Agfa 400, and Delta 400 all demonstrate classic S shape
> curves. Fuji Neopan 400 is unique, with a pronounced
> shoulder-excellent shadow separation and blow out proof highlights.
> EK has just changed TMAX 100, and the new curve does show less
> shoulder. HP-5 and FP-4 are pretty linear. TMAX 400 has no
> straightline-it is all extended toe, with increasing contrast with
> increasing exposure. Fuji Acros 100 can look kind of similar. Tri-X
> Professional 120 is the worst in this regard, extremely "scooped
> out", with much higher highlight contrast than shadow contrast.
>
> While the curves can be modified somewhat by different developers,
> the differences are real, and obvious on comparison prints (I have my
> 4x5 students shoot TMY and HP-5 in the same filmholder). There are
> obvious implications for scanning, as toggling through all
> Silverfast's Nega Fix profiles on a single image quickly
> demonstrates. 8 bit scanning software clearly makes assumptions about
> a (given) film's tonal characteristics, but those assumptions are
> obviously not based on the photographer's actual preferred EI,
> developer, and time.
>
> >However there are other limiting factors and experience tells me
> >that the thinnest possible negative that retains all the desired detail
> >yields the better print.
>
> Certainly true for condenser enlarger printing of small format negs.
> Large format, not so clear.

I have not found extra image density to be of any help with 4x5 in a cold
light enlarger either.
>
> >There is latitude but I think that this may still
> >hold for digital as well and is a function of the chemical nature of
film.
> >The toe does remain though but I wonder if PS doesn't give us a way to
> >straighten out a good portion of it.
>
> Yes, the "screen"  blending mode works wonders.
>
> >  >
> >>  I think if you use film and a scanner there is another calibration
step
> >>  to the zone system - camera, film, developer and scanner.
> >
> >Exactly. Which also speaks to the benefits of doing and controlling your
own
> >scanning.
>
> And another argument for scanning 16 bit.
>
> >In all fairness though I have not had any problems scanning
> >negatives that yielded good prints in the darkroom. So while additional
> >optimization can be done, I don't think that we are too far off the mark.
>
> The suggestion of cutting back development (N-1) makes sense, as does
> avoiding overdevelopment (especially with TMY and TXPro).

I will probably drop my own development times a bit, shoot for awhile and
see how I like the negs.
>
> I always calibrated my Zone System times for grade 2 paper by contact
> or diffusion head enlarger. That produces a fairly robust negative,
> and vibrant prints. But as I get more involve with digital, I expect
> to re-calibrate to grade 3 in order to have slightly thinner, more
> scannable negatives.

Just recalibrate to your digital output. <G>

Martin Wesley